Tips for evaluating damaged trees, planting new ones
The most common questions coming into the Extension Office are still regarding trees and their prognosis, so it’s time to revisit that topic. The Texas A&M Forest Service recently released a very comprehensive article regarding oak tree recovery, and the info is helpful for other struggling trees as well. In summary, the recommendation is to wait until July. If there are no leaves by July, the tree is dead. Fertilization is not recommended unless there is an obvious nutrient deficiency, and pesticide applications are not recommended unless there is an apparent insect or disease. If the canopy does put some leaves out but it still looks thin and weak, consider waiting until next year to re-evaluate. For more in-depth info, visit the article at https://tfsweb.tamu.edu/content/article.aspx?id=31600.
In the Concho Valley, there are some struggling oak trees, but ash trees are by far the more commonly freeze-damaged tree. Pomegranates, crape myrtles, Japanese Ligustrum and others were also widely killed to the ground, but these species are generally able to come back from the roots well. For those wanting to replace trees and shrubs, container-grown plants can be planted any time of year, but summer is the most difficult season to establish new woody plants. Fall, around October to November, is the best time of year to plant trees and shrubs.
When considering replacing trees and shrubs, carefully choose species that are well adapted or native to the area, and try to create a more diverse landscape. If there is only one type of shade tree used in the yard, something that is damaging or deadly to that species can take out all the trees. If there are various types of trees utilized in the landscape, the odds are much better that some will be fine. Try mixing it up with a few different trees – an oak, an elm, a pecan. For a list of recommended trees and shrubs for the Concho Valley, visit https://tomgreen.agrilife.org/horticulture/ and click on ‘Recommended Landscape Plants.” You can also check out the Texas Tree Selector at https://texastreeplanting.tamu.edu/ for a tool that helps you choose the right tree based on the site conditions and specific desired characteristics.
When planting new shrubs, till up and loosen up the soil in the bed and incorporate compost (unless planting desert shrubs or native plants that prefer ‘lean’ soil). But compost or any other soil amendments are not recommended for trees, since their roots grow too far and wide and they need to be well adapted to the native soil as it is. But do mulch trees and shrubs well with a thick layer of organic mulch to help them establish well (just not in a volcano shape – pull the mulch away from the trunk a few inches).
Allison Watkins is the Texas A&M AgriLife Extension Agent for horticulture in Tom Green County. Contact her at aewatkins@ag.tamu.edu.